If you have ever been frustrated trying to get an accurate plant population for an emergence issue using 1/1000th of an acre count there is a better method. For the last few years I have been using the measuring wheel method and have more confidence in my plant stands. The benefits of using this method are reduced ‘cherry picking’ of visually good or bad areas of the field, speed of count and improved accuracy of the count.

How does it work?

To use this method of population counts you push the measuring wheel and count 150 plants (I count by two’s, if you are really good you can count by three’s). When you reach a count of 150 plants, record the distance traveled in feet. Sorry no metric here record the measurement in feet. Repeat the count/measure three or four more times in the field or affected area. Average the measurement and convert using the following table by dividing the average number of feet for 150 plant count into the conversion factor. Example if I averaged 100 feet in a 30 inch row spacing the population would be 26,613 plants per acre (ppa) (2,613,600 divided by 100 feet = 26,136 ppa).

Also, assess non-emerged seedlings using the checklist in the Replant corn – How to decide article, by recording the population and the emergence issues we can make a good agronomic decisions for this year and future years.

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Due to the wet conditions this spring, the corn that did get planted is currently at pre-emergent to 1-2 leaf stage. If you were planning on making a pre-emergent application on emerged corn need please pay careful attention to their herbicide program so that you don’t risk crop injury and possible yield loss.*
So what are some of my options?
1. There’s still time to protect against yield loss from early weed competition. Going in pre to early post is the best choice to keep your fields clean during the critical weed free period.
2. Time is running short – choose a one-pass treatment that will take you through the season so you can avoid making a second application. One-pass and DONE.
3. Don’t spray glyphosate alone. Utilize a residual product(s) with your glyphosate to maximize your weed control, to reduce the need for a second application and help manage resistance on your farm.

For pre-emergent up to the 2 leaf stage of corn:
1) Stick to a pre-emergent application of Callisto® plus Primextra® II Magnum®. Or, if grassy weeds are getting beyond the 2-leaf stage in your glyphosate-tolerant corn, add in Touchdown Total®.

Beyond the 2-leaf stage up to 6-leaf corn (glyphosate tolerant corn):
If the corn crop has reached the 2-leaf stage, then switch to Halex® GT. Alternately, you could choose a tank-mix of Callisto + Primextra II Magnum + Touchdown Total for a one-pass contact and residual treatment.
*Refer to the label for a complete list of weeds, registered rates and timings. Please consult with your input supplier or local Syngenta representative for more information.

This year we had some fields that were planted early and then went thorugh a very wet, cold period and now the emergence is less than desirable in some areas of the field. Do I replant the poor sections, or the whole field (with the price of corn this would be a very costly option), do I leave it alone, these are all very good questions.

Corn replant decisions are difficult. The following table can be utilized as a guideline when assessing yield potential at various planting dates and populations. In general it doesn’t pay to replant corn where populations of healthy plants are greater than 18,000 plants per acre.

First we need to establish the population that has emerged. You can do this by counting the number of plants in 1/1000 of an acre (see chart). Do this a number of times in the field. Also, assess the cause of reduced emergence using the following checklist.

 Rotted seed or seedlings
 Sprout twisted or leaves expanded underground
 Seeds hollowed out (insect damage)
 Check seed intactness (firmness)
 If seed is watery or “yellowy pus” it is not going to emerge
 Do not worry about crooks or turns of the coleoptile (shoot) as it may be responding to the seed orientation (corn seed does have an up and down side); also, cold soil will often disorient coleoptile growth.

As this is a very difficult decision please contact your NK field representative or seed dealer if you have any questions.

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In Ontario and Quebec in 2011 we will have the majority of the corn planted after the optimum date of May 10th. What does this mean and what should our expectations be?

At the time of writing this (May 18th) it appeared we would be at least a couple of days before we could be back planting. Should we switch hybrids? I would recommend in the shorter growing season areas (<2750 CHU) switching now (drop 100 CHU per week delay but do not go below a 2600 CHU hybrid) and for mid range (2800 – 3000 CHU) switch around May 25th and rest of the area's do not switch until June. (reference: Switching to Earlier Hybrids).

What should we expect for yield this fall due to the delayed planting conditions this spring? First remember many other factors still affect yield other than planting date such as fertility, population, hybrid selection, weather, seed depth, compaction, etc…

Yield : expect to lose one bushel per day delay from May 10th or around 10% if delayed until June.

Harvest Moisture: On average expect one point of moisture increase for every four days delayed from May 10th. If delayed to early June a five point increase or 30% moisture compared to 25% if planted early.

Test Weight: Long term average is one pound of test weight loss for every 10 days delay in planting or 2 lbs if delayed to early June.

What can we expect if delayed to early June? 20 bu per acre ($100.00 per acre) plus on an expected 150 bu/ac crop $0.20/bu drying cost increase (assumed drying $0.04 per point per bu) equals $26.00 per acre. Assuming we do not lose grade due to reduced bushel weight a delay until early June could end up costing $126.00 per acre at $5.00 per bushel corn.

Let’s hope for a break in the weather and get this corn crop into the ground.

It is hard to be patient at this time of year. We all know that the sooner we can get started planted the better or is it? Yes and only if the conditions are right for quick emergence is this true. It takes approximately 100 – 150 CHU to emerge corn and with the daytime temperatures to date we have accumulated nothing in the way of heat units. If you have corn planted you are playing the waiting game to see when (if?) it is going to emerge. With our current genetics, quality standards and seed treatments seed can survive delayed emergence significantly better than 10 – 15 years ago, but if three to four weeks go by and we still have not seen the corn it will be hard to be patient and wish that you left it in the bag. So what should you do? Plant as soon as the soil is fit.

Should I start changing my hybrids to lower heat units? No. Prior to May 10, Syngenta Agronomy Research shows only a one bushel (or 0.11 bu/day) of corn yield loss with a ten day delay in planting. If you did not get finished planting until May 7th this year compared to April 28th last your expected yield loss is one bushel per acre. What about after May 10th? You may want to consider switching your very long heat unit corn to a shorter day hybrid and plant the rest. Our research has shown a one bushel per day for every day of delayed planting. What about May 24th? This topic will be discussed if delay occurs.

In the meantime we need to practice patience. Our elders were correct – patience is a virtue.

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Planting date: The calendar is not as important to observing ‘Mother Nature’. Soil temperature, 10 day forecast and soil conditions are more important than the calendar date. Research in the past few years have shown that earlier planted soybeans (May 1 – May 15) have preformed better than later planted. Soil Temperature – Soil temperature during the first 24 hours is critical to soybean emergence and vigour. Avoid planting soybeans when the soil temperature is below 10o C (50o F). Soybeans that absorb cold water during the first 24 hours are at a greater risk of poor germination and vigour. Soil temperature is usually 2 – 3 hours delay to air temperature. If you are planting into marginal soil temperature it is better to plant later in the day and watch 24 – 48 hour forecast in regards to temperature and avoid planting prior a cold forecast. For more information on soil temperature and soybeans check out: http://www.omafra.gov.on.ca/english/crops/field/news/croptalk/2003/ct_0903a7.htm

Seeding Rates – For early planted soybeans Use the recommended rate for the row width you are planting. Cutting rates is not recommended.

Seed Treatment – Planting into cooler soils will increase the risk of seed rots, seedling diseases and seed corn maggot. Due to the slower emergence of the soybean, the seed is exposed to the pest longer. Use seed treatments (Apron Maxx or Cruiser Maxx) to reduce the risk in early planted fields.

Planting Depth – Uniform seed depth is important. It is important to get the seed planted into moisture due to the high moisture required to swell the seed (50 % of its weight). The goal is place the seed approx. ½ inch into moisture. Ideal Planting depth should be between 1 – 1 ½ inches but anywhere from 1 – 2 ½ inches will work. Beans planted a 3 inches and deeper are at risk of emergence problems.

Soil Moisture Management – Wet soil conditions often lead to compaction (sidewall, surface) problems, deep planting issues and the seed trench opening up. When planting into wet soil conditions rolling or packing should be delayed to prevent compaction of the soil surface. When planting into dry soils it is very important to conserve the moisture by using the packer/roller during tillage and right after planting. Also, it is very important to not to over till the soil and/or till the soil to far ahead of planting as this practice may over dry the seed bed.